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usbip: fix stub_rx: harden CMD_SUBMIT path to handle malicious input

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commit c6688ef9f29762e65bce325ef4acd6c675806366 upstream.

Harden CMD_SUBMIT path to handle malicious input that could trigger
large memory allocations. Add checks to validate transfer_buffer_length
and number_of_packets to protect against bad input requesting for
unbounded memory allocations. Validate early in get_pipe() and return
failure.

Reported-by: Secunia Research <vuln@secunia.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Shuah Khan 2017-12-07 14:16:48 -07:00 • committed by Greg Kroah-Hartman
parent 80e733a9b3
commit b6f826ba10
1 changed files with 27 additions and 3 deletions
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30
drivers/usb/usbip/stub_rx.c
View file

@ -338,11 +338,13 @@ static struct stub_priv *stub_priv_alloc(struct stub_device *sdev,
return priv;
}
static int get_pipe(struct stub_device *sdev, int epnum, int dir)
static int get_pipe(struct stub_device *sdev, struct usbip_header *pdu)
{
struct usb_device *udev = sdev->udev;
struct usb_host_endpoint *ep;
struct usb_endpoint_descriptor *epd = NULL;
int epnum = pdu->base.ep;
int dir = pdu->base.direction;
if (epnum < 0 || epnum > 15)
goto err_ret;
@ -355,6 +357,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
goto err_ret;
epd = &ep->desc;
if (usb_endpoint_xfer_control(epd)) {
if (dir == USBIP_DIR_OUT)
return usb_sndctrlpipe(udev, epnum);
@ -377,6 +380,27 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
}
if (usb_endpoint_xfer_isoc(epd)) {
/* validate packet size and number of packets */
unsigned int maxp, packets, bytes;
#define USB_EP_MAXP_MULT_SHIFT 11
#define USB_EP_MAXP_MULT_MASK (3 << USB_EP_MAXP_MULT_SHIFT)
#define USB_EP_MAXP_MULT(m) \
(((m) & USB_EP_MAXP_MULT_MASK) >> USB_EP_MAXP_MULT_SHIFT)
maxp = usb_endpoint_maxp(epd);
maxp *= (USB_EP_MAXP_MULT(
__le16_to_cpu(epd->wMaxPacketSize)) + 1);
bytes = pdu->u.cmd_submit.transfer_buffer_length;
packets = DIV_ROUND_UP(bytes, maxp);
if (pdu->u.cmd_submit.number_of_packets < 0 ||
pdu->u.cmd_submit.number_of_packets > packets) {
dev_err(&sdev->udev->dev,
"CMD_SUBMIT: isoc invalid num packets %d\n",
pdu->u.cmd_submit.number_of_packets);
return -1;
}
if (dir == USBIP_DIR_OUT)
return usb_sndisocpipe(udev, epnum);
else
@ -385,7 +409,7 @@ static int get_pipe(struct stub_device *sdev, int epnum, int dir)
err_ret:
/* NOT REACHED */
dev_err(&sdev->udev->dev, "get pipe() invalid epnum %d\n", epnum);
dev_err(&sdev->udev->dev, "CMD_SUBMIT: invalid epnum %d\n", epnum);
return -1;
}
@ -450,7 +474,7 @@ static void stub_recv_cmd_submit(struct stub_device *sdev,
struct stub_priv *priv;
struct usbip_device *ud = &sdev->ud;
struct usb_device *udev = sdev->udev;
int pipe = get_pipe(sdev, pdu->base.ep, pdu->base.direction);
int pipe = get_pipe(sdev, pdu);
if (pipe == -1)
return;